KR100324359B1 - Refrigerator using two-stage expansion - Google Patents

Abstract

PURPOSE: A refrigerator using two-stage expansion is provided to prevent supercooling of refrigerant, and to improve performance of an evaporator in initial operation by decompressing high temperature and pressure condensed refrigerant and directly exchanging heat with refrigerant from the evaporator. CONSTITUTION: A refrigerator includes a compressor(21), a condenser(22) and freezing and refrigerating evaporators, and has a first expansion unit decompressing high pressure and temperature condensed refrigerant from the condenser in reaching the saturated liquid line; a heat exchange part(23) having a first pipe receiving decompressed refrigerant from the first expansion unit and a second pipe receiving refrigerant from the freezer evaporator; and a second expansion unit decompressing and supplying refrigerant from the first pipe to the freezer evaporator. The heat exchange part supplies cool refrigerant through the first pipe to the freezer evaporator, and supplies heated refrigerant through the second pipe to the compressor with exchanging heat between first and second pipes.

Description

Refrigerator using two stage expansion

The present invention relates to a refrigerator using two-stage expansion, and in particular, by reducing the refrigerant condensed at high pressure and high pressure by a condenser and then exchanging heat with the refrigerant flowing in a pipe used as a refrigerator evaporator to prevent excessive overcooling of the refrigerant and to perform initial operation. The present invention relates to a refrigerator using two-stage expansion to fully perform the function of a cold storage room evaporator.

In general, a refrigerator includes a freezing compartment and a refrigerating compartment, which are partitioned from each other, and mainly supplies cool air to each chamber through one evaporator. In addition, a so-called independent cooling method employing a separate evaporator in each chamber is adopted, and the situation is widely used as a method of controlling the internal temperature of each chamber by supplying cold air to the freezer compartment and the refrigerator compartment separately. Such an example is shown in FIG. 1.

1 is a configuration diagram of a refrigerator using two conventional evaporators, the compressor 1 compresses the refrigerant at high temperature and high pressure and supplies it to the condenser 2, and the condenser 2 condenses the refrigerant compressed at high temperature and high pressure. To supply the liquid refrigerant to the capillary tube 3. The capillary tube 3 surrounds the pipe at the inlet side supplied to the compressor 1, depressurizes the condensed liquid refrigerant to supply the refrigerator compartment evaporator 4, and the refrigerant evaporated in the refrigerator compartment evaporator 4 is a freezer compartment evaporator 5. And return to the compressor (1) in the state of low temperature and low pressure. 2 shows a pressure-enthalpy diagram in the circulation process of the refrigerant.

This independent cooling refrigerator has the advantage that it can deal with the increase of the load of the room more quickly than using a single evaporator, while using the two evaporators to increase the output of the compressor was more burdensome.

In order to solve this problem, in order to reduce the temperature difference between the inlet side and the outlet side of the compressor, as shown in FIG. 3, the pipe of the outlet side of the condenser and the pipe of the refrigerating chamber evaporator are mutually disposed to perform heat exchange. An intercooler method has been proposed. That is, the condenser 12 receives the refrigerant compressed by the compressor 11 at high temperature and high pressure, condenses it, and supplies the refrigerant to the first pipe 13a of the heat exchange unit 13. The high temperature and high pressure liquid refrigerant supplied to the first pipe 13a is cooled by heat exchange with the low temperature low pressure refrigerant flowing through the second pipe 13b of the heat exchanger 13 and then supplied to the expansion valve 14. The refrigerant supplied to the expansion valve 14 is depressurized and then evaporated in the freezer compartment evaporator 15 and then supplied to the second pipe 13b of the heat exchange unit 13 serving as a refrigerator compartment evaporator. The refrigerant supplied to the second pipe 13b is heated by heat exchange with the high temperature and high pressure refrigerant of the first pipe 13a, and then returns to the compressor 11 again. 4 shows a pressure-enthalpy diagram in the circulation of the refrigerant according to the intercooler method. In FIG. 4, the liquid refrigerant which has undergone the compression process L1 on the right side of the saturated steam line S2 and the condensation process L2 of the condenser 12 by the compressor 11 is the boundary point E of the saturated liquid line S1. When passing through, the heat exchange operation due to the temperature difference between the first pipe 13a and the second pipe 13b, ie, subcooled by ΔH, and then reduced by ΔP by the expansion valve 14 (L3). The refrigerant depressurized by the expansion valve 14 is evaporated while passing through the freezer compartment evaporator 15 and the second pipe 13b of the heat exchanger 13 in sequence (L4). In the freezer compartment evaporator 15 and the heat exchanger 13, a heat exchange operation is promoted by a cooling fan (not shown).

Such an intercooler-type refrigerator smoothly performs an evaporation action for supplying cold air to the freezer compartment and the refrigerating compartment as the supercooled refrigerant is decompressed through the heat exchange unit 13, and heats the evaporated refrigerant to supply it to the compressor 11. As a result, the output increase of the compressor 11 can be reduced.

However, in the conventional intercooler type refrigerator, since the heat exchange operation by the heat exchanger 13 is not actively progressed during the initial operation, it takes a certain time to normally perform the role of the refrigerator compartment evaporator. That is, the liquid refrigerant of high temperature and high pressure flows in the first pipe 13a during the initial operation, while the refrigerant passing through the freezer compartment evaporator 15 is exhausted by the evaporation of the freezer compartment due to the large load of the freezer compartment in the second pipe 13b. Low temperature refrigerant will not flow. That is, as shown in FIG. 5, the refrigerating chamber is required as the pipe temperature A on the outlet side of the first pipe 13a and the pipe temperature B on the inlet side of the second pipe 13b coincide with each other. There was a problem that inhibits the complete function as an evaporator.

In addition, since the refrigerant supercooled through the heat exchanger 13 is a liquid phase, the length of the capillary tube 14 may be longer than that of the case where the refrigerant in the gaseous phase is reduced in order to reduce the pressure by ΔP to meet the evaporation conditions of the low temperature and low pressure. .

An object of the present invention is to reduce the refrigerant condensed at high temperature and high pressure by the condenser in the refrigerator having an evaporator in the freezer compartment and the refrigerating compartment, and then directly exchanging heat with the refrigerant flowing through the pipe used as the refrigerator compartment evaporator to prevent excessive overcooling of the refrigerant. In addition, the present invention provides a refrigerator using two-stage expansion to completely perform the function of the refrigerator compartment evaporator during initial operation.

1 is a block diagram of a refrigerator using two evaporators according to the prior art,

2 is a pressure-enthalpy diagram of the refrigerant of FIG. 1;

3 is a configuration diagram of a refrigerator using one-stage expansion according to the prior art;

4 is a pressure-enthalpy diagram of the refrigerant of FIG.

5 is a temperature curve for the heat exchanger of FIG.

6 is a block diagram of a refrigerator using two-stage expansion according to the present invention,

7 is a pressure-enthalpy diagram of the refrigerant of FIG. 6;

8 is a temperature curve for the heat exchanger of FIG.

※ Explanation of code for main part of drawing

1,11,21: Compressor 2,12,22: Condenser

13,23: heat exchanger 14: expansion valve

15,25: freezer evaporator 24: second capillary tube

26: capillary 1

An object of the present invention as described above is a refrigerator having a compressor, a condenser and a freezer compartment evaporator and a refrigerator compartment evaporator installed in each of the freezing compartments and the refrigerating compartments which are separated from each other, and supplying cold air to each chamber, wherein the high temperature and high pressure condensed First expansion means for reducing the pressure when the refrigerant enters the saturated liquid line; It is disposed together with the first pipe receiving the refrigerant depressurized from the first expansion means and the second pipe receiving the refrigerant from the freezer compartment evaporator, and heat exchanges between the first pipe and the second pipe having different temperatures, A heat exchanger configured to supply the refrigerant cooled by heat exchange to the freezing chamber evaporator through the first pipe, and to supply the refrigerant heated by heat exchange to the compressor through the second pipe; And a second expansion means for depressurizing the refrigerant exchanged from the first pipe of the heat exchanger and supplying the refrigerant to the freezer compartment evaporator.

The present invention primarily reduces the refrigerant condensed at high temperature and high pressure through the first expansion means connected to the outlet side of the condenser, and reduces the refrigerant cooled by heat exchange to meet the evaporation conditions of low temperature and low pressure through the second expansion means. It is possible to prevent overcooling of the refrigerant and to fully perform the function of the refrigerator compartment evaporator during initial operation.

Although the first and second expansion means of the present invention uses a capillary tube, no limitation is imposed by using an expansion valve for reducing the refrigerant.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

6 is a block diagram of a refrigerator using two-stage expansion according to the present invention. As shown, the present invention includes a compressor 21 for compressing a refrigerant at high temperature and high pressure, a condenser 22 for condensing the refrigerant compressed at high temperature and high pressure, and a freezer chamber evaporator 25 for supplying cold air to the freezing chamber. . In addition, the present invention is the first capillary tube 26 to reduce the pressure when the high-temperature, high-pressure condensed refrigerant supplied from the condenser 22 enters the saturation liquid line, and the second refrigerant receiving the reduced pressure from the first capillary tube 26 A heat exchanger 23 in which a first pipe 23a and a second pipe 23b receiving refrigerant from the freezer compartment evaporator 25 are disposed and heat exchange is performed between the first pipe 23a and the second pipe 23b; And a second capillary tube 24 for reducing the refrigerant exchanged with the heat exchanged from the first pipe 23a of the heat exchanger 23 and supplying the refrigerant to the freezer compartment evaporator 25.

6 to 8 will be described the operation and effect on the refrigerator using the two-stage expansion according to the present invention having the configuration as described above.

First, the compressor 21 compresses at high temperature and high pressure according to the compression process L11 of FIG. 8, and the condenser 22 compresses the refrigerant compressed at high temperature and high pressure by the compressor 21. Condensation according to L12), and supplies the condensed high temperature and high pressure refrigerant to the first capillary tube (26). When the condensed liquid refrigerant enters the boundary point E1 of the saturated liquid line S11 of FIG. 7, the first capillary tube 26 reduces the pressure by ΔP1 according to the decompression process L13 of FIG. It supplies to the 1st piping 23a of (23). The pressure-reduced refrigerant in the first pipe 23a is cooled by heat exchange with the refrigerant flowing in the second pipe 23b according to the heat exchange process L14 of FIG. 7 and then supplied to the second capillary tube 24. The second capillary tube 24 depressurizes the refrigerant cooled by heat exchange at low temperature and low pressure to meet evaporation conditions according to the depressurization process (L15) of FIG. 7 and then supplies the refrigerant to the freezer compartment evaporator 25. Subsequently, as in the evaporation process L16 of FIG. 8, the freezer compartment evaporator 25 receives a low temperature low pressure refrigerant to perform an evaporation operation to supply cold air to the freezer compartment, and then the second pipe 23b of the heat exchange unit 23. And the second pipe 23b is supplied with the refrigerant from the freezer compartment evaporator 25 and heat-exchanged with the reduced pressure refrigerant in the first pipe 23a to return to the compressor 21 again. do.

The heat exchange part 23 is the first pipe 23a as the heat exchange operation is performed in a state in which the refrigerant supplied through the first pipe 23a is decompressed by ΔP1 through the first capillary tube 26 installed at the front end. ) And the heat exchange operation between the second pipe 23b is shortened and becomes active. In addition, the freezing chamber evaporator 25 and the heat exchanger 23 are accelerated by a cooling fan (not shown).

In the initial operation of the refrigerator, a refrigerant obtained by depressurizing a liquid refrigerant having a high temperature and high pressure flows into the first pipe 23a of the heat exchanger 23, and passes through the freezer chamber evaporator 15 to the second pipe 23b. Uncharged refrigerant flows. At this time, between the temperature of the refrigerant of the first pipe (23a) and the temperature of the refrigerant of the second pipe (23b) is a state before the active heat exchange operation is completed as in the normal operation, and then the refrigerant of FIG. Heat exchange from a time point when a predetermined time ta has elapsed, that is, a temperature curve, that is, when the outlet pipe temperature A11 of the first pipe 23a coincides with the pipe temperature of the inlet side B11 of the second pipe. The action becomes active.

The predetermined time ta required to reach the normal operation in the initial operation is shorter than that of the prior art, which is a refrigerant of the first pipe 23a decompressed by the first capillary tube 26 and the second pipe 23b. This is because the pressure difference ΔP2 of the coolant is relatively small.

The first pipe 23a and the second pipe 23b of the heat exchanger 23 serve as an evaporator for supplying cold air to the refrigerating chamber when the entire pipe is switched to normal operation after a predetermined time ta. do.

The first pipe 23a and the second pipe 23b are installed in close contact with each other. Preferably, the first pipe 23a and the second pipe 23b are fixed by welding to promote heat conduction.

Since the second capillary tube 24 reduces the reduced pressure at low temperature and low pressure to meet the evaporation conditions, the size of the reduced pressure is relatively reduced compared to the conventional one, and thus the length of the capillary tube is reduced.

The present invention as described above is to decompress the refrigerant condensed at high temperature and high pressure by the expansion means installed on the outlet side of the condenser, the reduced pressure refrigerant is cooled by heat exchange and then reduced to a low temperature low pressure to meet the evaporation conditions freezer chamber evaporator By passing through and circulating the refrigerant to return to the compressor in turn through the heat exchanger to prevent excessive overcooling of the refrigerant and has the effect of performing the function as a refrigerator compartment evaporator during the initial operation completely.

Claims (2)

In the refrigerator provided with a compressor, a condenser, a freezer compartment evaporator and a refrigerator compartment evaporator which are installed in the freezing compartment and the refrigerating compartment which are mutually separated, First expansion means for reducing the pressure by a predetermined pressure difference DELTA P1 so as not to overcool when the high temperature, high pressure condensed refrigerant supplied from the condenser enters the saturated liquid line; The first pipe receiving the refrigerant decompressed from the first expansion means and the second pipe receiving the refrigerant from the freezer compartment evaporator are in close contact with each other, and the refrigerant passing through the first pipe is cooled by heat exchange to the freezer compartment evaporator. While supplied, the refrigerant passing through the second pipe is heated by heat exchange to be supplied to the compressor, and used as the refrigerating chamber evaporator when it reaches a normal operation in which the outlet temperature of the first pipe is equal to the inlet temperature of the second pipe. Heat exchanger; And And a second expansion means for reducing the refrigerant cooled from the first pipe of the heat exchange part by a predetermined pressure difference (ΔP2) and supplying the refrigerant to the freezer compartment evaporator. The refrigerator according to claim 1, wherein the first and second expansion means are capillaries.